Imazethapyr effects on soil enzyme activity and nutrient uptake by weeds and greengram (Vigna radiata L.)

A field experiment was conducted to examine the effect of early post-emergence herbicide Imazethapyr 10% SL on soil enzyme activity (Dehydrogenase, Urease and Phosphatase) and nutrient uptake by weeds and greengram at Main Agricultural Research Station, Dharwad during kharif 2014. The treatments comprised of Imazethapyr 50g, Imazethapyr 62.5g, Imazethapyr 75g, Imazethapyr 50g with adjuvant, Imazethapyr 62.5g with adjuvant, Imazethapyr 75g with adjuvant, Quizalofop-ethyl 1000 ml, standard check (2IC + 2HW), weedy check and weed free check and was laid out in Randomized Complete Block Design with three replications.

Int.J.Curr.Microbiol.App.Sci (2017) 6(3): 247-253 International Journal of Current Microbiology and Applied Sciences ISSN: 2319-7706 Volume Number (2017) pp 247-253 Journal homepage: http://www.ijcmas.com Original Research Article https://doi.org/10.20546/ijcmas.2017.603.027 Imazethapyr Effects on Soil Enzyme Activity and Nutrient Uptake by Weeds and Greengram (Vigna radiata L.) Girdhari Lal1*, S.M Hiremath2 and Kailash Chandra3 Department of Agronomy, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi-221005, India Department of Agronomy, ARS, Gadag, UAS, Dharwad-580 005 (Karnatka), India Institute of Agricultural Sciences, Banaras Hindu University, Varanasi-221005, India *Corresponding author ABSTRACT Keywords Imazethapyr, Soil enzyme activity, NPK, Early postemergence, Greengram Article Info Accepted: 10 January 2017 Available Online: 10 March 2017 A field experiment was conducted to examine the effect of early post-emergence herbicide Imazethapyr 10% SL on soil enzyme activity (Dehydrogenase, Urease and Phosphatase) and nutrient uptake by weeds and greengram at Main Agricultural Research Station, Dharwad during kharif 2014 The treatments comprised of Imazethapyr 50g, Imazethapyr 62.5g, Imazethapyr 75g, Imazethapyr 50g with adjuvant, Imazethapyr 62.5g with adjuvant, Imazethapyr 75g with adjuvant, Quizalofop-ethyl 1000 ml, standard check (2IC + 2HW), weedy check and weed free check and was laid out in Randomized Complete Block Design with three replications Weed free check (T 10) recorded significantly higher dehydrogenase, urease and phosphatase activity recorded at seven & 15 days after spraying compared to all other treatments but was on par with T Among the different doses, higher dose of Imazethapyr (75 g a.i ha-1 with adjuvant) recorded lower dehydrogenase, urease and phosphatase activity of soil at seven and 15 days after spraying Weed free check (T 10) recorded significantly higher uptake of nutrients (NPK) by greengram compared to all other treatments but was on par with T Among the different doses, higher dose of Imazethapyr (75 g a.i ha-1 with adjuvant) recorded higher uptake of nutrients (NPK) by greengram Nutrients (NPK) uptake by weeds was higher in weedy check, but significantly lower in weed free, standard check and Imazethapyr treated plots Introduction Imazethapyr is a broad spectrum herbicide used as early post-emergence in pulses, oilseeds and leguminous crops Imazethapyr is an imidazole compound used as a selective herbicide The compound controls weeds by reducing the levels of three branched-chain aliphatic amino acids, isoleucine, leucine and valine, through the inhibition of aceto-lactate synthase (ALS), an enzyme common to the biosynthetic pathway for these amino acids Imazethapyr is used as post emergence or early post emergence at 20-25 DAS of soybean, greengram, blackgram and sunflower to control a variety of weeds However, intensive use of herbicides often lead to accumulation of active ingredients (or metabolites) of herbicides in agricultural soils These herbicides have potential to deteriorate the soil and water (of nearby 247 Int.J.Curr.Microbiol.App.Sci (2017) 6(3): 247-253 g a.i ha-1 + adjuvant @ 2.0 ml litre-1 of water (T4), Imazethapyr 10% SL @ 62.5 g a.i ha-1 + adjuvant @ 2.0 ml litre-1 of water (T5), Imazethapyr 10% SL @ 75 g a.i ha-1 + adjuvant @ 2.0 ml litre-1of water (T6), Quizalofop-ethyl 5% EC @ 1000 ml litre-1 of water (T7), standard check (2IC + 2HW at 20 and 40 DAS) (T8), weedy check (T9) and weed free check (T10) The experimental soil was black clayey soil (Vertisol) with the pH 7.4, organic carbon (8 g kg-1), available N (248 kg ha-1), available P2O5 (25.55 kg ha-1) and available K2O (396 kg ha-1) aquifers, rivers, lakes) and ultimately affect the soil microbial activity Nakatani et al., 2014 The quantity of herbicide available to the soil micro flora depends on different factors like: Soil nutrients, pH, temperature, and moisture content To determine the ecological toxicity of herbicides against soil microorganisms, the activities of different soil enzymes have to be analyzed The soil enzyme activity represents the total population of soil micro flora The soil enzyme activity reacts faster than physical activity of soil Therefore, they can beused as an early warning bioindicator against the changes occur in soil (Baćmaga et al., 2015; Franco- Andreu et al., 2016; Saha Ajoy et al., 2016 So far, contrasting results have been observed by various researchers evaluating the impact of imazethapyr on soil microbial biomass and enzymatic activities Lupwayi et al., 2004 reported that application of Imazethapyr decreased the soil microbial biomass, microbial diversity and carbon content Green gram variety ‘Nirmal Gold (NVL-1)’ was sown on 14th July 2014 at 30 x 10 cm spacing using seed rate of 12 kg ha-1 The recommended fertilizers i.e 25:50 kg ha-1 N and P2O5 were applied at the time of sowing The total rainfall received during crop growth period was 604.2 mm and was well distributed The early post-emergence herbicide Imazethapyr was sprayed at 23 DAS and other herbicide such as Quizalofopethyl was sprayed at the same time Nutrients are very much essential for growth and development for green gram and there deficiency leads to decrease the crop yield Therefore, it is necessary to know the uptake of nutrients by crop and weeds Komal et al., 2015 reported that Imazethapyr reduces density of weeds, resulting lower uptake of NPK by weeds and higher by crop Soil sampling The soil sampling was done randomly from each plot i.e., and 15 days after spraying of herbicides Samples were taken from the top (0–15 cm) layer of soil using a soil auger and mixed thoroughly to prepare one homogeneous composite sample after removing plant materials Materials and Methods A field experiment with 10 treatments and three replications laid out in randomized complete block design was undertaken at Main Agricultural Research Station, University of Agricultural Sciences, Dharwad (Karnataka) during kharif season of 2014 The treatments comprised of Imazethapyr 10% SL @ 50 g a.i ha-1 (T1), Imazethapyr 10% SL @ 62.5 g a.i ha-1 (T2), Imazethapyr 10% SL @ 75 g a.i ha-1 (T3), Imazethapyr 10% SL @ 50 Soil enzyme activity assay Dehydrogenase (DHA) activity was estimated by monitoring the rate of production of triphenylformazan (TPF) from substrate 2, 3, 4-tri-phenyl tetrazolium chloride (TTC) (Casida et al., 1964) Phosphatase activity in soil was assayed from the amount of ρnitrophenol released (Evazi and Tabatabai, 1979) The procedure adopted to determine 248 Int.J.Curr.Microbiol.App.Sci (2017) 6(3): 247-253 the urease activity of soil was essentially the same as adopted by Pancholy and Rice (1973) except the ammonia liberated due to hydrolysis used in the reaction mixture was determined by nesslerization as described by Jackson (1973) Results and Discussion Effect of Imazethapyr as EPOE herbicide on soil enzyme activity Dehydrogenase activity (DHA) (g TPFg-1 soil day-1) Estimation of N, P and K uptake by crop and weed Dehydrogenase is as an intra-cellular enzyme and related to microbial respiratory processes Hence, death of cells or propagation leads to increase or decrease of DHA, and therefore, it is an indication of overall behavior of microbial population of the soils Among the herbicide treated plots application of Imazethapyr @ 75 g a.i ha-1 + Adjuvant @ 2.0 ml ha-1 of water recorded lower dehydrogenase activity (Table 1) at seven days after spray but was on par with rest of the doses The higher dehydrogenase activity was observed in weed free check when compared to all other treatments, but on par with Standard check Quizalofop-ethyl @ 1000 ml ha-1 also recorded lower dehydrogenase activity but higher than Imazethapyr treated plots To estimate the uptake of N, P and K by crop and weeds, samples were collected at 60 DAS and at harvest The samples were oven dried at 650 C and ground in Willey mill to pass through two mm sieve The two mm sieved samples were used for the estimation of nitrogen, phosphorus and potassium content in crop and weeds Nitrogen uptake by crop and weeds were determined by digesting the plant samples with suitable acid mixture of concentrated sulphuric acid The digested samples were distilled by Microkjeldhal method in an alkaline condition and titrated against standard acid Piper (2002) Phosphorus was estimated by Vanedomolybdate method in diacid mixture as detailed by Jackson (1973) The intensity of the colour developed was measured in a spectrophotometer, using blue filter Potassium content was estimated from diacid digest material using Flame Photometer as described by Muhr et al., (1965) and was expressed as percentage K The nutrient content and dry weight were used to calculate the total uptake of nutrients (N P K) and expressed in kg ha-1 The similar trend was observed at 15 days after spray of herbicides but DHA was increased Imazethapyr decreased the DHA from the 7th day onwards after the treatment and persisted only up to the 15th days in peanut (Saha Ajoy et al., 2016) Moreno et al., (2007) said that DHA was stable possibly due to a stress process of soil microorganisms which helped to maintain constant values But at higher doses of Imazethapyr suppression of DHA was observed, which may be due to the lethal action of Imazethapyr on soil microorganisms (Jyot et al., 2015), which, in turn, affect the enzymatic chemical process owing high concentration of herbicides as well as the toxicity of the metabolites, produced from the herbicides at later stages (Sabale et al., 2015) Nutrient uptake (kg ha-1) = Nutrient content (%) × Dry weight (kg ha-1) 100 249 Int.J.Curr.Microbiol.App.Sci (2017) 6(3): 247-253 Urease activity (μg NH4-N g-1 soil day-1) compared to days after spraying and the effect of herbicide was decreased Many studies reported that urease activity reduced or decreased due to herbicide application (Riah et al., 2014; Saha Ajoy et al., 2016 reported that urease activity decreased with Imazethapyr (7 to 15 days after spray) at different doses Majumdar et al., (2010) revealed that urease activity of soil inhibited by the application of Quizalofop-p-ethyl Urease, a key hydrolyzing enzyme, mediates the hydrolysis of urea into carbon dioxide and ammonia and hence plays a very important role in the nitrogen cycle in soils Urease activity of the soil was significantly influenced by application of herbicides Application of Imazethapyr @ 75 g a.i ha-1 + Adjuvant @ 2.0 ml ha-1 of water as EPOE herbicide recorded lower Urease activity (Table 1) at seven days after spray The higher Urease activity was observed in weed free check when compared to all other treatments, but on par with Standard check Quizalofop-ethyl @ 1000 ml ha-1 also recorded lower Urease activity but higher than Imazethapyr treated plots The similar trend was observed at 15 days after spray of herbicides but urease activity was increased Phosphatases activity (g pnpg-1 soil hr-1) At seven days after spray of herbicides, the higher phosphatase activity was observed in weed free check However, Standard check was on par with weed free check Application of Imazethapyr 75 g a.i ha-1with or without adjuvant recorded lower phosphatase activity Table.1 Soil enzyme activity as influenced by weed control treatments in green gram Treatment T1 T2 T3 T4 T5 T6 T7 T8 T9 T10 S.Em± CD (5%) Dehydrogenase activity (µg TPF g-1 soil day1 ) days 15 days after after sprayin spraying g 25.17 34.88 25.00 34.32 23.15 32.21 24.83 34.07 24.27 33.36 23.84 31.73 30.85 32.32 38.35 41.03 34.08 35.02 38.46 41.24 0.93 1.08 2.78 3.21 Urease activity (µg NH4 N g-1 soil day-1) Phosphatases activity (µg pnp g-1 soil hr-1) days after spraying 15 days after spraying days after spraying 15 days after spraying 3.12 2.96 2.68 3.08 2.92 2.66 3.28 4.62 4.28 4.68 0.07 0.23 3.92 3.88 3.66 3.90 3.84 3.56 4.15 4.55 4.20 4.58 0.11 0.33 94.41 92.23 86.42 94.25 90.67 85.66 88.37 112.42 102.95 116.46 3.20 9.51 118.45 117.23 107.36 116.88 114.42 106.47 112.32 110.57 103.85 113.33 3.52 NS 250 Int.J.Curr.Microbiol.App.Sci (2017) 6(3): 247-253 Table.2 Nitrogen, phosphorus and potash uptake (kg ha-1) by weeds and greengram as influenced by weed control treatments NPK uptake (kg ha-1) by weeds Treatment 60 DAS At harvest N P K N P K 11.30 2.45 8.32 11.47 2.62 8.63 T1 10.39 2.28 7.58 10.52 2.43 7.92 T2 9.08 2.06 6.91 9.19 2.20 7.20 T3 9.08 1.98 6.46 9.21 2.12 6.79 T4 8.19 1.89 6.07 8.32 2.02 6.38 T5 4.90 1.11 3.67 4.96 1.18 3.89 T6 10.83 2.33 7.67 10.97 2.49 8.02 T7 3.56 0.87 2.78 3.61 0.93 2.93 T8 28.91 6.26 20.22 29.50 6.68 21.27 T9 0.64 0.16 0.50 0.70 0.18 0.57 T10 1.04 0.22 0.70 1.08 0.24 0.85 S.Em± 3.11 0.67 2.09 3.22 0.71 2.53 CD (5%) All other doses of Imazethapyr have recorded lower soil phosphatase activity, but higher dose has more effect than lower dose Quizalofopethyl @ 1000 ml ha-1 also recorded lower phosphatase activity but higher than Imazethapyr treated plots At 15 days after spray of herbicides there was no significant difference was observed in phosphatase activity (Table 1) Strong inhibition of acid phosphate activity was observed due to application of Imazethapyr (Perucci et al., 2000), whereas increase in the activity was 10 times Majumdar et al., (2010) reported that early negative effect on acid phosphatase activity and alkaline phosphatase activity were observed due to application of quizalofop-p-ethyl Many researchers observed that some herbicides may inhibit acid phosphatae and stimulate alkaline phosphatase activity and vice versa (Cycon et al., 2012) Alkaline phosphatase activity was increased by application of Imazethapyr after initial inhibition at higher doses and at later stages, but prolonged inhibition was observed for acid phosphatase (Saha Ajoy et al., 2016) NPK uptake (kg ha-1) by greengram 60 DAS At harvest N P K N P K 61.76 15.87 57.84 37.65 9.87 36.58 67.53 16.94 62.78 38.03 10.00 36.45 74.91 21.23 75.79 41.06 11.84 42.22 70.16 18.39 67.09 39.94 10.81 39.09 79.81 21.90 76.52 44.49 12.34 42.95 88.71 23.81 85.17 50.36 13.67 49.06 71.40 18.52 65.44 39.81 10.48 37.34 93.44 26.21 90.19 53.14 15.20 51.76 54.03 13.82 50.96 32.69 8.49 31.77 93.90 26.31 90.25 54.78 15.61 52.68 2.58 0.96 2.37 1.51 0.41 1.51 7.69 2.85 7.06 4.49 1.24 4.49 free check compared to all other treatments However, Standard check also recorded lower uptake of nitrogen (3.56 kg ha-1) but on par with Imazethapyr @ 75 g a.i ha-1 + Adjuvant @ 2.0 ml litre-1 of water (4.90 kg ha-1) This is due to the effective control of weeds by herbicides Significantly higher nitrogen uptake (28.91 kg ha-1) was recorded in weedy check, which results from higher number of weeds present in this treatment Similar trend was observed at harvest At 60 DAS, significantly lower uptake of phosphorus (0.16 kg ha-1) was recorded in weed free check However, Standard check also recorded lower uptake of phosphorus (0.87 kg ha-1), but on par with Imazethapyr @ 75 g a.i ha-1 + Adjuvant @ 2.0 ml litre-1 of water (1.11 kg ha-1) Significantly higher phosphorus uptake (6.26 kg ha-1) was recorded in weedy check Similar trend was observed at harvest At 60 DAS, significantly lower uptake of potassium (0.50 kg ha-1) was recorded in weed free check (T10) compared to all other treatments However, Standard check (2 IC + HW at 20 and 40 DAS) (T8) also recorded lower uptake of potassium (2.78 kg ha-1) compared to T5, T4, T3, T2, T7, T1 and T9 treatments, but on par with T6 Imazethapyr @ 75 g a.i ha-1 + Adjuvant @ 2.0 ml litre-1 of water (3.67 kg ha-1) Significantly higher potassium uptake (20.22 kg ha-1) was recorded in weedy check (T9) Similar trend was Effect of Imazethapyr herbicide on nutrient (NPK) uptake by weeds At 60 DAS, significantly lower uptake of nitrogen (0.64 kg ha-1) was recorded in weed 251 Int.J.Curr.Microbiol.App.Sci (2017) 6(3): 247-253 observed at harvest The results on uptake of nutrients (NPK) by weeds are in line with the findings of Habimana Sylvestre et al., 2013; Vijayalaxmi et al., 2012; Parchant et al., 2015 and Komal et al., 2015 In conclusion Application of Imazethapyr @ 75 g a.i ha-1 + adjuvant @ ml litre-1 of water recorded significantly lower Dehydrogenase, Urease and Phosphatase activity due to toxic effect of Imazethapyr Higher soil enzyme activity was observed where no herbicides were applied Application of Imazethapyr @ 75 g a.i ha-1 + adjuvant @ ml litre-1 of water recorded higher uptake of nutrients by greengram and lower by weeds Effect of Imazethapyr herbicide on nutrient (NPK) uptake by greengram Significant variations were observed with NPK uptake by greengram recorded at 60 DAS and harvest At 60 DAS, nitrogen uptake by greengram was observed significantly higher in weed free check (93.90 kg ha-1) However, Standard check (93.44 kg ha-1) and Imazethapyr @ 75 g a.i ha-1 + Adjuvant @ 2.0 ml litre-1 of water (88.71 kg ha-1) remained on par with weed free check Weedy check recorded significantly lower uptake of nitrogen by greengram (54.03 kg ha-1) Similar trend was observed at harvest At 60 DAS, phosphorus uptake by greengram was observed significantly higher in weed free check (26.31 kg ha-1) However, Standard check (26.21 kg ha-1) and Imazethapyr @ 75 g a.i ha-1 + Adjuvant @ 2.0 ml litre-1 of water (23.81 kg ha-1) remained on par with weed free check (T10) Weedy check recorded significantly lower uptake of phosphorus by greengram (13.82 kg ha-1) Similar trend was observed at harvest At 60 DAS, potassium uptake by greengram was observed significantly higher in weed free check (90.25 kg ha-1), but on par with Standard check (90.19 kg ha-1) and Imazethapyr @ 75 g a.i ha-1 + Adjuvant @ 2.0 ml litre-1 of water (48.91 kg ha-1) Weedy check recorded significantly lower uptake of potassium by greengram (30.15 kg ha-1) Similar trend was observed at harvest The higher uptake of NPK by greengram in weed free, standard check and Imazethapyr treated treatments were due to reduction in dry matter of weeds and less cropweed competition for different resources likelight, moisture, nutrients and CO2 (Table 2) The results on nutrients (NPK) uptake by greengram are in conformity with the findings of Parchant et al., 2015; Komal et al., 2015; Shruthi et al., 2015; Habimana Sylvestre et al., 2013 and Vijayalaxmi et al., 2012 References Baćmaga, M., Borowik, A., Kucharski, J., Tomkiel, M., Wyszkowska, J 2015 Microbial and enzymatic activity of soil contaminated with a mixture of diflufenican + mesosulfuron-methyl + iodosulfuron-methylsodium Environ Sci Pollut Res., 22: 643–656 Casida, L.E., Klein, D.A., Santoro, T 1964 Soil science J Soil Sci., 98(6): 371-376 Cycon, M., Piotrowska-Seget, Z., Kozdroj, J 2012 Responses of indigenous microorganisms to a fungicidal mixture of mancozeb and dimethomorph added to sandy soils Int Biodeter Biodegrr., 64: 316–323 Evazi, Z and Tabatabai, M.A 1979 Phosphatase in soils Soil Biol Biochem., 9: 167 - 172 Franco-Andreu, L., Gómez, I., Parrado, J., García, C., Hernández, T., Tejada, M 2016 Behavior of two pesticides in a soil subjected to severe drought Effects on soil biology Appl Soil Ecol., 105: 17– 24 Habimana, S., Kalyana Murthy, K N., Shankaralingappa, B C., Sanjay, M T., Ramachandra, C 2013 Nutrient uptake and yield of soybean (Glycine max L.) as influenced by pre and post-emergence herbicides European J Experimental Bio., 5: 33-40 Jackson, M L 1973 Soil Chemical Analysis, Prentice Hall of India Pvt Ltd., New Delhi Jyot, G., Mandal, K., Singh, B 2015 Effect of 252 Int.J.Curr.Microbiol.App.Sci (2017) 6(3): 247-253 dehydrogenase, phosphatase and urease activity in cotton soil after applying thiamethoxam as seed treatment Environ Monit Assess, 187(5): 1–7 Komal, Singh, S.P., Yadav, R.S 2015 Effect of weed management on growth, yield and nutrient uptake of greengram Indian J Weed Sci., 47(2): 206-210 Lupwayi, N.Z., Harker, K.N., Clayton, G.W., Turkington, T.K., Rice, W.A., O’Donovan, J.T 2004 Soil microbial biomass and diversity after herbicide application Can J Plant Sci., 84: 677– 685 Majumdar, B., Saha, A.R., Sarkar, S., Maji, B., Mahapatra, B.S 2010 Effect of herbicides and fungicides application on fibre yield and nutrient uptake by jute (Corchorus olitorius), residual nutrient status and soil quality Indian J Agric Sci., 80(10): 878–883 Muhr, G.R., Datta, N.P., Shankarambramoney, R., Lelley, V.R., Donahue, R.L 1965 Soil Testing in India USAID, New Delhi, 47-77 Nakatani, A.S., Fernandes, M.F., De Souza, R.A., da Silva, A.P., dos Reis-Junior, F B., Mendes, I.C., Hungria, M 2014 Effects of the glyphosateresistance gene and of herbicides applied to the soybean crop on soil microbial biomass and enzymes Field Crops Res., 162: 20–29 Pancholy, S.K., Rice, F.L 1973 Soil enzyme in relation to old field succession: amylase, cellulose, invertage, dehydrogenese and urease, Soil Sci Soc Am Proc., 47-50 Perucci, P., Dumontet, S., Bufo, S.A., Mazzatura, A., Casucci, C 2000 Effects of organic amendment and herbicide treatment on soil microbial biomass Biol Fert Soils, 32: 17–23 Piper, C S 2002 Soil and Plant Analysis, Hans Publ Bombay, India Prachand, Smita, K.J., Kubde, Sujata Bankar, 2015 Effect of chemical weed control on weed parameters, growth, yield attributes, yield and economics in soybean (Glycine max) Trends in Biosci., 8(2): 539-542 Riah, W., Laval, K., Laroche-Ajzenberg, E., Mougin, C., Latour, X., TrinsoutrotGattin, I 2014 Effects of pesticides on soil enzymes: a review Environ Chem Lett., 12: 257–273 Sabale, R.P., Shabeer, T.P.A., Utture, S.C., Banerjee, K., Oulkar, D.P., Adsule, P G., Deshmukh, M B 2015 Kresoxim methyl dissipation kinetics and its residue effect on soil extra-cellular and intra-cellular enzymatic activity in four different soils of India J Environ Sci Health, Part B, 50(2): 90–98 Saha, A., Bhaduri, D., Pipariya, A., and Jain, N.K 2016 Influence of Imazethapyr and Quizalofop-p-ethyl application on microbial biomass and enzymatic activity in peanut grown soil Environ Sci Pollution Res., 23(23): 23758-23771 Shruthi, G.K., Salakinkop, S.R., Patil, H.Y 2015 Effect of sequential application of pre and post-emergence herbicides on nutrients uptake by crop and weeds in kharif greengram Int J Trop Agric., Vol.33(2): 703-708 Vijayalaxmi, G.S., Hiremath, S.M., Hosmath, J.A., Patil, P.L., Doddamani, M.B 2012 Sequential application of pre and post emergence herbicides in soybean (Glycine max L.) Karnataka J Agric Sci., 25(2): 262-263 How to cite this article: Girdhari lal, S.M Hiremath and Kailash Chandra 2017 Imazethapyr Effects on Soil Enzyme Activity and Nutrient Uptake by Weeds and Greengram (Vigna radiata L.) Int.J.Curr.Microbiol.App.Sci 6(3): 247-253 doi: https://doi.org/10.20546/ijcmas.2017.603.027 253 ... described by Jackson (1973) Results and Discussion Effect of Imazethapyr as EPOE herbicide on soil enzyme activity Dehydrogenase activity (DHA) (g TPFg-1 soil day-1) Estimation of N, P and K uptake by. .. S.M Hiremath and Kailash Chandra 2017 Imazethapyr Effects on Soil Enzyme Activity and Nutrient Uptake by Weeds and Greengram (Vigna radiata L.) Int.J.Curr.Microbiol.App.Sci 6(3): 247-253 doi:... greengram and lower by weeds Effect of Imazethapyr herbicide on nutrient (NPK) uptake by greengram Significant variations were observed with NPK uptake by greengram recorded at 60 DAS and harvest At